Have had 2 people out to fix this no luck yet. Furnace is a 12 year old Carrier Model: 58MCA120 Multipoise gas-fired condensing furnace (I admit I'm a woman who is just reading this from the brochure).
The noise sounds mechanical (somewhat squealy/grindey) and starts up maybe 15-30 seconds before the heat comes on, and then stops when the heat starts blowing out. It's been doing this for at least 6 weeks, very obvious throughout the house, yet was difficult for the repair people to catch because furnace has some sort of delay thing when you make it turn on by upping thermostat. I do leave the blower on continuously but one of the fixer people replaced that and it made no difference. Any ideas of what this could be and how to have them fix it? p.s. the heat is working perfectly.
Thanks so much.
Roberta
